http://www.perlmonks.org?node_id=621855


in reply to Re^3: how to pull in all params that are numbered
in thread how to pull in all params that are numbered

The problem is that while does not iterate over a list, it simply checks for a true value. For example, while (1){} will run forever, whereas for (1){} will run once.

The same behaviour occurs when test being evaluated is param(). Additionally, while (param()){} will not modify $_. Perhaps you tested the script without any arguments, in which case it would have behaved as expected.

Here is a simple test:

#!/usr/bin/perl use strict; use warnings; use CGI qw(param); my $runs =0; my @num; print "Content-type: text/plain\n\n"; while(param()) { printf "run %d\n", $runs++; if ($runs > 10) { print "Ran over 10 times\n"; exit; } }
You can verify it by adding the parameters on the commandline, e.g.
perl foo.pl a=b